Formation of diazoate intermediate upon nitrous acid and nitric oxide treatment of 2′-deoxyadenosine

When 2′-deoxyadenosine was treated with HNO2 or NO, a small amount of a previously unidentified product was formed. The product was also formed by the reaction of 2′-deoxyadenosine with isoamyl nitrite in tetrahydrofuran as a major product. The product was identified as a diazoate derivative of 2′-deoxyadenosine, a reaction intermediate. At the initial stage of the HNO2 or NO reaction, the concentration of the diazoate was greater than or comparable to 2′-deoxyinosine, a deamination product of 2′-deoxyadenosine. The diazoate was fairly stable and decomposed with a half-life of 66 h at pH 7.4 and 37 °C. These results suggest that the diazoate can be formed in cellular nucleosides or DNA with biologically relevant dose of HNO2 and NO.